This invention relates to transducers and, more particularly, to a multi-turn, binary shaft position encoder.
Shaft position encoders have many industrial uses. One such use is to generate electrical signals representative of the position of a workpiece in automatic machine-tool control. Accuracy, reliability, compactness, and cost are the factors upon which a systems engineer selects a shaft position encoder. These characteristics are therefore essential considerations in the design of a shaft position encoder.
To generate electrical signals representative of a large number of shaft positions, multi-turn encoders are utilized. A multi-turn encoder has a plurality of coded discs geared together to rotate at different related speeds. In my monograph entitled "How to Use Shaft Encoders," Datex Corporation, 1965, pp. 37-39, the problem of the ambiguity introduced by the gearing of multi-turn encoders is discussed. In this connection, there is a brief description of an approach that employs a redundant or overlapping bit on the low-speed encoder to resolve ambiguity. To my knowledge, this method has never been fully developed or used in any commercial encoders.